🔍 Key Concepts

• Watertight doors below the bulkhead deck / waterline requirements in SOLAS and 46 CFR • Difference between sliding doors and swinging (hinged) doors in terms of tightness and operation under flooding • Why certain door types are restricted in locations that may be submerged

💭 Think About

• Think about which door designs are safest and most reliable if water pressure is acting directly on them from flooding. • Consider which types of doors can be remotely or automatically closed from the bridge or a central control station. • Ask yourself: in a real flooding emergency, which type of door is least likely to jam or be forced open by water pressure?

✅ Before You Answer

• Verify which door types are explicitly allowed below the waterline by regulation (vertical vs horizontal sliding vs hinged). • Check whether swinging (hinged) doors are generally accepted as watertight where there is a risk of pressure from both sides, or if they are more limited in use. • Confirm that the permitted types below the waterline must be capable of power operation and remote control in many passenger and cargo ship regulations.